Our group has focused on catalyst-enabling synthetic chemistry with broad directions, including applications in pharmaceuticals, plant/animal chemical biology, π-conjugated materials, and molecular nanocarbons. In this talk, I will describe the overview and some of our recently developed C-H activation catalysts. We have shown that the C-H activation can streamline the synthesis of pharmaceutically relevant molecules and natural products. In this talk, we will also demonstrate the power of C-H activation in the discovery of new small molecules that can control plant growth and mammalian biological clocks. We have also shown that the site-selective π-extension by C-H activation is an ideal methodology for preparing organic π-materials and molecular nanocarbons. In this talk, the controlled synthesis of nanographenes and the discovery of three-dimensional warped nanographenes enabled by C-H activation will be also described.